ISLAMABAD, Pakistan (CNN) -- Pakistani military officials raised the death tolls in two Sunday attacks in the country's tribal region.

The death toll from a missile strike on a compound in South Waziristan rose from seven to 20, military sources said. And the death toll from a suicide bombing at a security checkpoint in Mohmand Agency went from four to 11, military sources said.

Earlier Sunday, another military source said an unmanned U.S. drone was suspected to have fired the missile in the South Waziristan incident.

White House spokesman Gordon Johndroe said he had no comment on the report, and a CIA spokesperson also declined comment.

Two missiles were dropped on the compound in the village of Badar Sunday night, the source said. He did not want his name revealed because he is not authorized to speak to the media.

The United States has in the past offered no comment on such strikes in Pakistan, citing policy.

Military officials have said South Waziristan is the stronghold of Pakistani Taliban leader Beitullah Mehsud.